Apparatus for signaling by electromagnetic waves.



No. 706,747. Patented Aug. I2, I902.

n. A. EESSENDEN.

- APPARATUS FOR SIGNALING BY ELECTROMAGNETIC WAVES.

(Application fllad m 22, 1902. (No Model.) v

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To all whom it mayconcern:

UNITED ST ES PATENT OFFICE.

REGINALIS A. FESSENDEN, or. MANTEO, NORTH CAROLINA.

APPARATUS FOR SIGNALING V at ELECTROMAGNETIC, waves.

sracrrrcan'rotr forming part a: Lcttcra remit No. 706,747, dated August 12,1902.

Original application flled September 88, 1901, Serial No. 78.887: Divided and this application iiled July 22, 1902, g m

- 6r488- (No model.)

Be it known that I, REGINALD A. FEssEN- DEN, acitizen of the United States, residing at Manteo, in the county of Dare and State of North Carolina, have invented or discovcred certain new and usef ul Improvements in I Apparatus 'for Signaling by Electromagnetic Waves, of which improvements the following wavesor impulses and the modification of the character of the waves by sound-waves or other desired means and of suitable mechanism or apparatus at the receiving-station operative by the waves or' impulses from the sending-station to give a signal or indication.

By the term electromagnetic waves as a used herein is meant waves of a wave length long in comparison with the wave length oi! what are commonly, called heat-waves or radiant heat. By grounded conductor is meant a conductor grounded eitherdirectly or throngha capacity, an i ductance, or a resistance, so that thecurren in the conductor flows from the conductor to ground, and vice versa, when the electromagnetic waves are generated.

The invention is hereinafter more fully described aud claimed. j V

In the accompanying drawings, forming a part of this specification, Figure 1 is a diagrammatic view illustrating forms of apparatus for the sending and receiving stations.

Fig. 2 is a similar view illustrating a modification oi! the sending apparatus, and" Fig. 3 illustrates a further modification ot the sending apparatus. y

In the practice of my invention I provide at the sending-station a conductor 1, of suitable construction and arrangement, and connect the same to one terminal of a coil 2, surrounding a core 3, preferably annular in shape other terminal of the coil is connected to one of-theknobsor terminals 4 of. an inductioncoil or other suitable generator 6, capable of producing practically continuous and rapid oscillations in the conductor. The other terminal 5 of the generator is connected to ground. A second coil 7, forming a part of the circuit for the battery 8, is placed on the core 3, and a transmitter 9, preferably micro-' phonic in construction, or other mechanism capable of modifying the current in the circuit is included in the circuit of the battery and coil 7. A capacity 18 and inductance 19 are connected in shunt to the spark-gap for the purpose of maintaining sustained osciliations of practically constant frequency.

-The capacity 18 and inductance 19 should be arranged to have the same period of oscillation as the receiving-conductor 10 and the sending-conductor 1. It will be seen that the circuit containing capacity 18 and inductance 19 being connected across the spark-gap forms a parallel circuit in thesending-conducto'r 1.,

whose aerial and grounded sections are also connected across the spark-gap. On account of the fact that the circuit '18 19 and the sending-conductorl are in parallel and not in 86' ries the difference of potential across'these two circuits is the same, while the currents in the two circuits are diiierent, this conphone-diaphragm 12,formed 0'! metal orconsisting of insulating material having a metal plate or coil of wire secured thereto orlany other suitable construction adapted to vibrate in unison with changes of current produced by the waves radiated fromthe sending-station, is suitably supported in operative relation to the coil 11. The apparatus at thereceiving-station is tuned or made resonant by V sending -condnctor 1. The terms tuned .and resonant are used herein one to'in-Q part of the diaphragm, through induced-curis modified or changed, as by speaking. into the transmitter, the permeability of the core .plication Serial No; 62,301, filed March 29,

-..rent is set up in the conductor 10, as by waves of vibration of thesending-conductor 1, which -is'thereby thrown out of resonance with a the waves or impulses given 0d bylthe contions willproducecorresponding'changes in .To this end the conductor 1' is connected to a at the'conductor i is'chang'ed, correspondingly altering the intensity of the waves or v V impulses generated by the'conductor.

periodicity-as, for example, of fifty then any suitable means known in the art to theclude the'othcr. When an alternating curorimpulses from the sending-station, such current acts to repel or attract the diaphragm. according to the time constant of the metal theosci-liations'in thesending-conductor; but

when the current in the circuitof the coil 7.

8 is correspondingly changed or modified, thereby producing a corresponding change or modification in the self inductance and a change in the frequency or the natural period resonating circuit 18 19, connected in parallel to said sending-conductor 1, and due to this failure in resonance, producingn corresponding change or modification in the intensity of ductor 1 and in thc'inteusity oi the oscilla-. tions produced in the receiving-conductor. The changes in the intensity of theoscillnthe mean positionof the diaphragm 12, such changes corresponding to the vibrations of the diaphragm of the transmitter, exactly reproducing any of the waves or impulses which aife'cted the transmitter. The same result maybe eflected by changing the capacity of the conductor 1, as shown in Fig. 2.

fixed plate 13 of a condenser, while the other plate 14 is formed by or connected to a diaphragm capable of responding to waves or impulses. As the plate 14 in vibrating moves toward or from the other plate the capacity Instead of using an induction-coiland sparkgap an alternating-current generator of high sand per secondmay be used, as shown in. Fig. 3. It is preferred that the generator should be of the character described in ap- 1901. One terminal of the generator 15 is connected to the sending-conductor and the other terminal to ground. A microphonic contact' 16 may be interposed, as shown,- in the circuit of the sending generator and conductor, the microphonic contact forming part of a carbon transmitter, the diaphragm of which is indicated at 17. The microphonic contact should be of the kind used in what are known as speaking arc-lights and ca-- :art, and hence ah pable of working with currents oi, ten to one i ural period in resonance with the period oil I the dynamo, and the amount of the-resonant voltage depends upon the resistance of the microphoniccontact. Hencespeakingagainst 'ihe diaphragm the amount of the voltage is changed to correspond with the sound-waves. 'lhis microphonic" contact 'may also be used in place ot-th'e'varlable inductance shown in 'F'ig. 1 orthe'variable capacity shown in Fig.

2in connection with the induction-coil and the auxiliary circuit 18 19.

Itis characteristic of my improvement that waves or impulses are generated at the sending-station and received at the other station' and that the signaling is effected not by interruption of the flow of waves or impulses, but bya modification or change'in' the character of the waves or impulses. Many ways ily suggest themselves to those skilled in the regards the broader features of my invention I do not limit myself to any particular mechanism for modifying the waves orimpulses. The term signaling is used herein in a broad sense, and especially as including the transmission and receipt of words, sounds, characters, &c.'

No claim is madeherein to my improved method of signaling by electromagneticwavcs or impulses as"'thesame forms the subjectmatter of application Serial No. 76,837, filed September 28, 1901.

I claim herein as my invention 1. In a system of signaling by electromagnetic waves, the combination of means forthe practically continuous generation ct electromagneticwaves-or impulses, means for modifying or changing the character of such waves or impulses without interruption of their continuity, and an indicating means or mechanism at the receiving-station operative by the electromagnetic waves or in] pulses, substantially as set forth.

2. In a system of signaling by electromagnetic waves,the'com'blnation of means for the of modifying or changing the waves will r'eadpractically continuous generation of electro- 3. In a system of signaling by electromag netic waves, the combination ofmeans for generating electromagnetic waves or impulses, means for modifying or varying the character of a portion 0! such waves or impulses without interruption of their contiunity, and an indicating mechanism at the receiving-station operative by the electromagnetic waves or impulses, substantiallyas set forth. w j

4. In a system of signaling by electromagnetic waves, the combination of means for the generation ofelectromagnetic waves or lmpulses'of uniform character, means for continuously modifying or varying the character of a portion of such wavps or impulses without interruption of their continuity and an Indicating mechanism at the receiving-station operative by the electromagnetic waves sound waves or impulses-for modifying or varying the character of the electromagnetic waves or impulses without interruption of their continuity, andmechanismat the receiving-station operative. by the electromagnetic waves or impulses, forth. a

6. In a system of signaling by electromagnetic waves, the combination of means for the practically continuous generation of electromagnetic waves or impulses normally of a predetermined character, means for changing' the electrical constants of the sendingconductor so as to change the degree of resonance between the generator and the sending-conductor and thereby modify or change the character of such waves or impnlses'without interrupting their continuity, and mechanism at the receiving-stationoperative by the electromagnetic waves or impulses, substantially as set forth.

7. In a system'of signaling by electromag-' netic waves, the, combination of means for the practically continuous generation of electromagnetic waves or impulses, means for modifying or changing the intensity of said waves or impulses without interrupting their continuity and a receiving-conductor tuned .to correspond with the sending-conductor,

whereby the receiving-conductor will" be effected by the electromagnetic waves or impulses during only a portion of the time, substantially as set forth. v

8. In a system of signaling by electromagnetic waves,'the combination of means for the practically continuous generation of electromagnetic waves or impulses, and means for changing the resistance in the sendingconductor, thereby modifying or changing the intensity of the electromagnetic waves or impulses without interrupting their continuity, substantially as set forth? 9. .Ina system of signaling by electromagnetic waves, the combination of means for the practically continuous generation of electromag'netic waves or impulses/ normally of a predetermined, character, means for modifyingor changing the characterof such waves or impulses withoutinterruption of theircontion operative by the electromagnetic waves or impulses, substantially as set forth.

10. In a system of signalingby electromagnetic waves, the combinatioh of means for the substantially asset 1 practically continuous generation of electromagnetic waves or impulses normally of a predetermined character, means for continuously modifying or changing the character of such waves or impulses without interruptiou of their continuity and indicating mechanism sounds by electromagnetic waves, the combi nation of means for the generation of electromagnetic waves' or impulses normally of uniform character and means operative by sound waves or impulses for modifying or changing the character of the electromagnetic waves or b impulses without interruption of their continuity, substantially as set forth.

12. In a system of signaling by electromagnetic waves, the combination of means for thepractically continuous generation of electromagnetic waves or impulses of uniform character, means for modifying the character of said waves or impulses without interruption of their continuity and indicating mechanism at the receiving-station operative by the elec tromagnetic waves or impulses, substantially as set forth.

13. In a system of signaling by electromagnetic waves or impulses, the combination of means for the practically continuous generation of electromagnetic waves or impulses of constant periodicity, means for modifying or changing the intensity of such waves without interruption of their continuity and an indicating mechanism at the receiving-station operative by the electromagnetic waves or impulses, substantiallyas set forth.

14. In a system for transmission of speech by. electromagnetic waves the combination at the sending-station of means for the. practically continuous generation of electromagnetic waves a telephone-transmitter for modi-' fying the character of the waves or impulses, and a telephone-receiver at the receivingstation responsive to currents generated by the electromagnetic waves, substantially as set forth.

' 1-5.. In a system of signaling by electromagnetic waves, the combination of means for the practically continuous generation of electro-- magnetic waves or impulses of constant periodicity, means for changing the resistance of the sending-conductor, thereby modifying or changing the intensity'of such'waves or impulses without interruption of theirtcontinuity,-and an indicating mechanism at the receiving-station operative by the electromag- ?9ti0 waves or impulses,substantiallyas set orth.

In testimony whereof I lrave hereunto set my hand. A tinuity, and -echanism at the receiving-sta- REGINALD l ESSENDEN.

Witnesses:

LOUIS DORMAN, Ovu) S'r. MARIE. 

